/**
 * 
 */
package com.yullage.ann.common;

/**
 * @author Yu-chun Huang
 * 
 */
public class ActivationFunction {

	private ActivationFunction() {
		// Prevent from instantiation.
	}

	public static double sigmoid(double x) {
		return 1.0 / (1.0 + (Math.exp(-x)));
	}

	public static double bipolarContinuousFunction(double x) {
		return 2.0 / (1.0 + (Math.exp(-x))) - 1;
	}
}
